DETERMINATION OF APPROPRIATE RECORDING FORCE FOR NONINVASIVE MEASUREMENT OF ARTERIAL-PRESSURE PULSES

1. Non-invasive recording techniques of the arterial pressure pulse wi ll distort the arterial wall and may alter pulse wave measurements, We hypothesized that intersubject variability of these measurements woul d be reduced if recording forces were normalized to reflect individual ized arterial occlusion forces, 2. In 10 normal male subjects (age 24 +/- 1 years), brachial, radial and finger arterial pressure pulses wer e recorded simultaneously using volume displacement pulse transducers (Fukuda TY-303) rand a finger pressure monitoring system (Finapres, Oh meda 2300) and were made at 2, 5 and 10-100% (10% increments) of the b rachial arterial force associated with marked distortion of finger pul sations, Forces were applied at the brachial site in a randomized orde r while a constant 1.8 N force was applied at the radial artery site, Pressure pulses were analysed using the discrete fast Fourier transfor m, 3. Pulse amplitude, contour, wave velocity and relative transmissio n ratios remained relatively constant until the brachial artery record ing force exceeded 59.9 +/- 0.3% of the largest recording force used i n each subject (7.14 +/- 0.75 N), The finger pulse pressures (P<0.0001 ), radial pulse amplitudes (P<0.0001) and contours (harmonics 2-6, P<0 .003), pulse wave velocity (P<0.021) and relative transmission ratios (harmonics 3-7, P<0.01) then decreased with higher recording forces, 4 . To avoid distortion, non-invasive recordings of arterial pressure pu lse amplitude, contour, pressure wave velocity and relative transmissi on ratios along a peripheral arterial segment should use recording for ces of less than 60% of the force associated with marked distortion of finger pulsations.